Gas metal arc welding (GMAW) is very commonly used to weld metals of a wide range of types, wherein an arc welding apparatus is combined with a shielding gas apparatus for providing a gas shield at the weld site. The shielding gas may be an inert gas, such as argon or helium, a generally non-reactive gas, such as carbon dioxide, or combinations thereof, including other gases, such as oxygen. The choice of shielding gas depends generally upon the type of metal being welded.
As known in the art, a GMAW apparatus utilizes a source of electric current, usually D.C., which is provided to an electrode. From the tip of the electrode, the current passes to a workpiece separated therefrom a short distance, whereupon welding of the workpiece transpires while the shielding gas floods the environment of the welding. To provide GMAW in a safe and efficient manner, a welding gun is used which provides user or robotic control, and includes a GMAW nozzle whereat are disposed the electrode and the delivery orifice for the shielding gas. Examples welding guns are exemplified in U.S. Pat. No. 4,954,690 and U.S. Pat. No. 7,105,775.
Turning attention to FIGS. 1A through 1C, the details of a typical GMAW nozzle will be discussed.
As shown generally at FIGS. 1A and 1B, a GMAW nozzle assembly 10 includes a GMAW nozzle 12 removably connected by a threaded section 10a to a gooseneck component 14 of a welding gun. The GMAW nozzle 12 includes a generally cylindrical shield housing 16 having an open end 16a. The gooseneck component 14 includes: an internal electrode feeder 18 to which is connected a wire-like electrode 20 having an electrode tip 20a projecting from the open end of the shield housing; an electrode contact tube 22 for delivering welding electrical current to the electrode, and a shielding gas passage 24, including communicating orifices 24a through which the shielding gas G is delivered into the shield housing 16 so as to streamingly exit therefrom at the open end 16a thereof.
As shown at FIG. 1C, after a period of operation of the GMAW nozzle assembly 10, the internal shield surface 16b of the shield housing has accumulated welding spatter 26 which has obstructed the open end 16a. This condition is quite problematic, as it can not only restrict or misdirect the streaming flow of the shielding gas, it can adversely affect the proper function of the electrode. Either of these problems can have an adverse affect on the quality of the weld provided to the workpiece. Thus, required is a periodic maintenance regimen to clear accumulated debris and replace the GMAW nozzle in the event the debris cannot be cleared. The need to regularly service the nozzle shield results in added expenses, including down time for the GMAW apparatus.
Accordingly, what remains needed in the art is to somehow provide a GMAW nozzle assembly that does not suffer from the debilitations of welding spatter accumulation as presently plagues the current state of the art of GMAW nozzles.